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Heat Transfer
 Heat transfer research that supports the improvement of HVAC&R equipment performance is conducted on a fundamental basis. Currently, there are two focuses in heat transfer. First, the Group measures and models two-phase refrigerant/lubricant mixtures heat transfer including flow boiling and pool boiling. In support of this effort, a technique was developed to measure the lubricant excess surface density using the fluorescent properties of lubricant. The measurement technique has been instrumental in the development of a semi-theoretical pool-boiling model for refrigerant/lubricant mixtures. The model can be used to select lubricants that improve the evaporator performance of chillers. In addition to boiling and evaporation, condensation studies are also conducted along with the evaluation of the performance of brazed-plate heat exchangers. A second relatively newer focus of the Group is the measurement of single-phase heat transfer in a micro-channel. The research was initiated in support of the design of a DNA chip and it is anticipated that the project will develop fundemental insight that will help in the development of microfluidic devices for HVAC&R equipment and building controls.
Mark Kedzierski
HVAC&R Equipment Performance Group
(301) 975-5282
mark.kedzierski@nist.gov
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